Google Slides is an online presentation app that lets you create and format presentations and work with other people.
You can also download free Slides templates from the following websites:
Slidesgo
Slides Carnival
SlidesMania
Here are some free game templates for Google Slides.
Board Game Template
Word Game Template
Deal or No Deal Template
Cardtegories Template
To learn more, take the self-paced Slides (Part 1, Part 2, and Part 3) training at the Google Applied Digital Skills website.